1. Field of the Invention
The present invention relates to a production process for a semiconductor device having metal electrodes such as bumps provided on its surface.
2. Description of Related Art
Some of semiconductor chips have metal electrodes such as bumps projecting from a surface thereof. For example, such a semiconductor chip may be mounted on a printed wiring board by flip-chip bonding, or bonded to another semiconductor chip in a stacked relation to form a semiconductor device of chip-on-chip structure.
In general, the semiconductor chip has an insulating film and an aluminum interconnection film provided on a surface of a semiconductor substrate which serves as a base thereof, and connection pads for external electrical connection provided in proper positions on the surface thereof. A protective film covering the outermost surface of the semiconductor substrate is formed with openings which expose the connection pads therethrough.
A process for forming the bumps generally comprises the steps of: forming a seed film on the entire surface of a wafer formed with a protective film; forming on the seed film a resist film having openings just above the connection pads by patterning; and selectively depositing a metal material for the bumps to a great thickness in the openings formed in the resist film. Thereafter, the resist film is removed, and then the seed film except bump portions thereof is removed. Thus, island-like bumps electrically connected to the respective connection pads are provided.
As can be understood from the foregoing, the formation of the bumps requires complicated steps such as the formation of the resist film on a wafer-by-wafer basis, so that the process involves an increased number of steps thereby hindering the reduction in the production cost of the semiconductor chip.